/* -*- c++ -*- */
/*
 * Copyright 2017 Glenn Richardson <glenn@spacequest.com>
 *
 * This file is part of gr-satellites
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "varlen_packet_framer_impl.h"
#include <gnuradio/io_signature.h>
#include <cstdio>
#include <ctime>
#include <iostream>

extern "C" {
#include "golay24.h"
#include "libfec/fec.h"
}

namespace gr {
namespace satellites {

varlen_packet_framer::sptr
varlen_packet_framer::make(const std::string& packet_key,
                           int length_field_size,
                           endianness_t endianness,
                           bool use_golay,
                           const std::vector<uint8_t> sync_word)
{
    return gnuradio::get_initial_sptr(new varlen_packet_framer_impl(
        packet_key, length_field_size, endianness, use_golay, sync_word));
}

varlen_packet_framer_impl::varlen_packet_framer_impl(const std::string& packet_key,
                                                     int length_field_size,
                                                     endianness_t endianness,
                                                     bool use_golay,
                                                     const std::vector<uint8_t> sync_word)
    : gr::block("varlen_packet_framer",
                io_signature::make(1, 1, sizeof(char)),
                io_signature::make(1, 1, sizeof(char))),
      d_header_length(length_field_size),
      d_use_golay(use_golay),
      d_sync_word(sync_word),
      d_endianness(endianness),
      d_ninput_items_required(1)
{
    d_packet_tag = pmt::string_to_symbol(packet_key);

    set_tag_propagation_policy(TPP_DONT);

    for (size_t ii = 0; ii < d_sync_word.size(); ii++) {
        d_sync_word.at(ii) = d_sync_word[ii] & 0x01;
    }

    d_header_length = ((d_header_length + 7) / 8) * 8;
    d_header_length = std::max(32, std::min(8, d_header_length));

    if (d_use_golay)
        d_header_length = 24;

#ifdef VLPF_DEBUG_TIMING
    d_last_debug1 = std::time(NULL);
    d_last_debug2 = std::time(NULL);
    d_start_time = std::time(NULL);
#endif
}


varlen_packet_framer_impl::~varlen_packet_framer_impl() {}

void varlen_packet_framer_impl::forecast(int noutput_items,
                                         gr_vector_int& ninput_items_required)
{
    unsigned ninputs = ninput_items_required.size();
    for (unsigned i = 0; i < ninputs; i++)
        ninput_items_required[i] = d_ninput_items_required;
}

int varlen_packet_framer_impl::general_work(int noutput_items,
                                            gr_vector_int& ninput_items,
                                            gr_vector_const_void_star& input_items,
                                            gr_vector_void_star& output_items)
{
    const unsigned char* in = (const unsigned char*)input_items[0];
    unsigned char* out = (unsigned char*)output_items[0];
    int packet_len = 0;
    std::vector<tag_t> tags;

    uint32_t header = 0;
    unsigned int asm_len = d_sync_word.size();

    // find the next packet_tag
    get_tags_in_range(
        tags, 0, nitems_read(0), nitems_read(0) + ninput_items[0], d_packet_tag);
    if (tags.size() > 0) {
        // check for packet size
        packet_len = to_uint64(tags[0].value);

        if ((unsigned)noutput_items < packet_len + d_header_length + asm_len) {
            set_min_noutput_items(packet_len + d_header_length + asm_len);
#ifdef VLPF_DEBUG_TIMING
            if (std::time(NULL) - d_last_debug1 > 1) {
                std::cout << (std::time(NULL) - d_start_time)
                          << "nouput:" << noutput_items
                          << " req:" << (packet_len + d_header_length + asm_len)
                          << std::endl;
                d_last_debug1 = std::time(NULL);
            }
#endif
            return 0;
        }
        set_min_noutput_items(1);

        d_ninput_items_required = tags[0].offset - nitems_read(0) + packet_len;
        if (ninput_items[0] >= d_ninput_items_required) {
            // copy the option sync word
            if (asm_len > 0) {
                memcpy(out, (const void*)&d_sync_word[0], asm_len);
                out += asm_len;
            }

            // create the length field header
            header = packet_len / 8;
            if (d_use_golay) {
                encode_golay24(&header);
            }

            // copy header
            if (d_endianness == GR_MSB_FIRST) {
                for (int ii = 0; ii < d_header_length; ii++) {
                    out[ii] = (header >> (d_header_length - ii - 1)) & 0x01;
                }
            } else {
                for (int ii = 0; ii < d_header_length; ii++) {
                    out[ii] = (header >> ii) & 0x01;
                }
            }

            // copy data and tag
            memcpy(&out[d_header_length], in, packet_len);
            add_item_tag(0,
                         nitems_written(0),
                         d_packet_tag,
                         pmt::from_long(packet_len + d_header_length + asm_len),
                         alias_pmt());
            consume_each(packet_len);

#ifdef VLPF_DEBUG_TIMING
            std::cout << (std::time(NULL) - d_start_time) << ":\tASM Framed @ "
                      << nitems_written(0) << " len " << packet_len << std::endl;
            std::cout << "\tread: " << nitems_read(0) << "\tini:  " << ninput_items[0]
                      << "\touti: " << noutput_items << std::endl;
#endif
            GR_LOG_DEBUG(d_debug_logger,
                         boost::format("%d byte packet output @ %ld") % packet_len %
                             nitems_written(0));
            d_ninput_items_required = 1; // d_header_length + asm_len + 1; // abs min
            return packet_len + d_header_length + asm_len;
        } else {
#ifdef VLPF_DEBUG_TIMING
            if (std::time(NULL) - d_last_debug2 >= 1) {
                std::cout << (std::time(NULL) - d_start_time)
                          << ":\tASM not enough input:" << ninput_items[0]
                          << " req:" << d_ninput_items_required << std::endl;
                d_last_debug2 = std::time(NULL);
            }
#endif
        }
    }
    return 0;
}


} /* namespace satellites */
} /* namespace gr */
